1. Field of the Invention
The present invention relates to a bearing device, a method of manufacturing the bearing device, and an information recording/reproducing apparatus.
2. Background Art
In the related art, information recording/reproducing apparatuses, such as hard disks, which make various kinds of information recorded and reproduced with respect to disks (equivalent to a “magnetic recording medium” of the claims), have been known. Generally, information recording/reproducing apparatuses include a head gimbal assembly equipped with a slider that records and reproduces signals with respect to a disk, and an arm (equivalent to a “rotating member” of the claims) having the head gimbal assembly mounted on a tip side. The arm is made rotatable by a bearing device provided on a base end side. By rotating the arm, the slider can be moved to a predetermined position of a disk so as to perform recording and reproducing of signals.
Generally, bearing devices includes a shaft, and a pair of rolling bearings that are inserted into the shaft and are arranged side by side in the axial direction of the shaft. Additionally, the pair of rolling bearings each include an inner ring fixed to the shaft, an outer ring surrounding the inner ring, a reinforcing sleeve that covers the outer ring, and a plurality of rolling elements that are arranged between the inner ring and the outer ring. The arm is externally fitted to the outer ring via the sleeve.
Incidentally, in recent years, in order to cope with further reduction in size, thickness, and cost of the information recording/reproducing apparatuses, further reduction in size, thickness, and cost of bearing devices assembled into the information recording/reproducing apparatuses is required.
Thus, for example, JP-A-2001-208082 discloses a bearing device that includes a pair of outer rings arranged side by side in an axial direction via a spacer and in which the outer rings are formed so as to be thicker than the outer rings of the bearing devices in the related art, and a tolerance ring that fixes the outer rings to each other is provided to eliminate a sleeve.
According to JP-A-2001-208082, the sleeve is eliminated, so that the number of bearing parts can be reduced and the number of assembling steps of the bearings and the manufacturing cost thereof can be reduced, and the outer rings are made thicker, so that it is possible to withstand a high load. Therefore, reduction in size of the bearing device can be realized.